"insurance", in my opinion, isprecautionary measures to attempt to ensure things go smoothly once things are out of your control. Nobody ever has 100 precent control of a situation, ESPECIALLY while hunting, and therfore marksmanship is never a garuntees tool that can be relied upon 100 percent of the time. It doesn't matter who you are or how much you practice, eventually bad shots are gonna come out the end of your rifle and you are going to be held responsible for them. For that simple fact alone, hunters should feel the burden of ensuring that when that bad shot is taken, that they have taken the proper measures before going into the field to ensure thata bad shot causes an animal minimal amountsof pain/stress/agony as possible. One of those measures to be taken is the responsibilty of the hunter to make sure he has enough gun to take down an animal if his shot isnt 100 percent accurate. BY having a small caliber, you are increasing your margin of error and therfore limiting your ability to take down an animal ethically.I'm not saying that it cant be done because I haveseen it done affectively, but a marginally or slightly-off bad shotwith a 22, is far worse for you and the deer than a marginally or slightly-off bad shot with a .300 caliber rifle.
Back to the original question: Yeah, you could use a 6mm and knock him dead in the dirt on the first shot. However, ifsomeone made a marginal shot that would not have been marginal with a reasonably larger caliber that the person is capable ofshooting just aswell with, thenthey just willingly created a situation that wasnt neccessary and caused an animal a lot of unneccessary pain.
I know, its just my opinion,andopinions are like a-holes, everybody's got one and they all stink
